松辽盆地中生界火山岩储层特征及对气藏的控制作用

火山岩储层是松辽盆地深层天然气勘探的主要目的层,分布上主要受深大断裂控制,沿断裂成带分布,不仅分布在山岭地区也广泛分布在断陷盆地的沉积地层中;储集空间为原生气孔、杏仁体内孔、次生的斑晶溶蚀孔、基质内溶孔和构造溶蚀裂缝;孔隙结构组合为单一裂缝及斑晶溶蚀孔与裂缝组合而成的孔隙结构;在成因上分为喷发溢流时形成原生气孔,喷发间歇期受风化淋滤形成次生孔隙及在埋藏过程中成岩、构造作用的影响 3个阶段;裂缝是改善火山岩储层性能的关键因素,成岩作用既加剧了次生孔隙的充填也加剧了溶蚀孔隙的形成,压实作用对储层物性没有影响。火山岩在烃源岩中相对独立的分布使其具有得天独厚的成藏条件,构造运动和后期风化剥蚀是控制储层物性的主要因素,断裂的发育程度控制了气藏的分布。

CHARACTERISTICS OF MESOZOIC VOLCANIC ROCKS AND ITS CONTROLLING EFFECT ON GAS RESERVOIR IN SONGLIAO BASIN

Volcanic rock reservoir is a main target layer for deep gas exploration in Songliao basin, controlled chiefly in distribution by deep and major fractures showing widespread in belt along the fracture not only in mountainous areas but also in sedimentary layers in the fault subsidence basins; Space of the reservoir are observed to be primary bubble pores, amygdale interior pores, secondary phenocryst \{solution\} pores, \{matrix\} dissolution pores, structural solution \{fissures.\} Pore structural assemblies are discovered to be pore structures made up of unitary fissures, phenocryst \{solution\} pores and fissure assemblies. Three stages can be divided in terms of origin namely; primary bubble pores formed in the period of overflow eruption, secondary pores originated by the \{process\} of weathering eluviation in the \{period\} of eruption intermittent and diagenesis and structure effects in the burial process. Fissures are key factors for the improvement of property of volcanic rock reservoir, diagenesis either intensified secondary pore fillings or intensified the formation of solution \{fissures,\}compaction has no an effect on the reservoir property . Relatively independent \{distribution\} of volcanic rocks in hydrocarbon source rocks make it possible for them to have exceptional advantages for the formation of reservoir, tectonic movements and deuteric weathering-erosions are main factors for controlling \{property\} of the reservoir ,development of fractures controls the distribution of gas reservoir.